Drosera flexicaulis Welw. ex Oliv.

Rjosk, A., Neinhuis, C., Monizi, M. & Lautenschläger, T., 2022, Synopsis of the genus Drosera (Droseraceae) in Angola and the Democratic Republic of the Congo, Blumea - Biodiversity, Evolution and Biogeography of Plants 67 (1), pp. 1-14 : 7-9

5. Drosera flexicaulis Welw. ex Oliv. — Fig. 7

Drosera flexicaulis Welw.ex Oliv.(1871) 403; Diels (1906) 98; G.C.C. Gilbert (1951) 554;A.S.Rob. et al. (2017) 1398. —

Lectotype (designated by Diels (1906) 98): F.M.J. Welwitsch 1181 (lecto LISU), Angola, Huíla, Lopollo , Dec. 1859.

Perennial herb, caulescent. Stems up to 25 cm long, erect, slender, glabrous ( Fig. 7b ). Leaves alternate, clustered somewhat into a rosette towards the apex, all leaves including lower leaves mostly erect or ascending (sometimes reflexed); stipules 1–2 mm long, connate at the base, apex lacerated, ferrugine- ous; lamina lanceolate, narrowly spathulate-ovate or spathulate, 3–15 by 1–5 mm, bearing tentacles adaxially and around the margins, glabrous or sparsely pilose abaxially ( Fig. 7a ); petioles 0.5–3.2 cm long, slender, glabrous or sparsely pilose. Inflorescences cymose, with 3–13 flowers; peduncles 1–4 together, 8–21(–30) cm long, ascending, glabrous;bracts filiform to linear, c. 2 mm long, caducous; pedicels 1–10 mm long, erect, glabrous or sparsely pilose. Sepals 5, oblong to lanceolate, 4–7 by 1–2 mm, connate at the base, sparsely pilose to pilose. Petals 5, obovate, 5–8 by 2.5–4 mm, white or purple. Stamens 5, filaments 4–5 mm long. Pollen in tetrads, tetrads c. 45–52 µm diam, single grains c. 25–30 µm diam, echinate ( Fig. 7e ), echini conical, c. 2 mm long, in low density, with short clavate sculptural elements between echini. Pistil: ovary subglobose to ovoid, c. 2 by 1 mm, glabrous; styles 3, c. 2.5 mm long, 2-partite to the base. Seeds fusiform, 0.7–0.9 by c. 0.2 mm, black, shiny, testa reticulate.

Distribution — Angola, DRC, Zambia ( Fig. 7c ).

Habitat & Ecology — Grows on sand and peat, in grassy swamps, seasonally dry wet-savannah.

Additional specimens (see Fig.7d for province map). ANGOLA, Bié, junto à margem do rio Chitembo,alt. 1500 m, 31 Oct.1966, Teixeira et al. 10901 ( BR) ; Cusseque – TFO core site , hilly landscape, fire in last dry season, S13°42' E17°5', 19 Oct. 2012, M. Finckh 135547 ( HBG) ; Cusseque – TFO core site , plain:alluvial plain,fire in last dry season, S13°41' E17°6',alt. 1515 m, 29 Oct. 2011, M. Finckh 132756 ( HBG) ; Cuando Cubango, Menongue, Vila Serpa Pinto , pr. da confluencia do Cambumbé com o Cuebe, alt. 1420 m, 12 Feb. 1960, E.J. Mendes 2484 ( BR, COI) ; Menongue, andados 14 km de Vila Serpa Pinto para Longa, vale do Cambumbé ,alt. 1430 m, 26 Feb.1960, E.J. Mendes 2754 ( COI) ; Cuanza Sul, am Longa oberh. Minnesera , alt. 1230 m, 1 Feb.1900, H. Baum 687 ( HBG) ; Lunda Sul, Saurimo , 25 Oct.1932, R.G.N. Young 1167 ( COI) . – DRC, Haut-Katanga, 6 km à l’WNW de la touree Oee de la Lut., Plateau des Kundelungu , alt. 1680 m, 25 Mar. 1969, S. Lisowski et al. 3789 ( BR) ; près de la touree Oee de la Lut., Plateau des Kundelungu ,alt. 1670 m, 26 Mar. 1969, S. Lisowski et al. 3552 ( BR) ; 2 km a l’E des tourees de la Lut., Plateau des Kundelungu , alt. 1600 m, 8 Jan. 1971, S. Lisowski et al. 13079 ( BR) ; Lualaba, Plateau de la Manika ( environs Katentania ), Nov. 1912, Homblé 774 ( BR) ; village Matoki , Plateau de la Manika, alt. 1400 m, 20 Jan. 1969, S. Liswoski et al. 5 ( BR) ; Kisoté , Plateau de la Manika, alt. 1500 m, 5 Apr. 1969, S. Lisowski et al. 4181 ( BR) ; 2 km à l’W de la riviere Musonai vers le village Djoni, Plateau de la Manika, alt. 1420 m, 23 Mar. 1969, S. Lisowski et al. 5651 ( BR) .

Note — This species has been treated as a synonym of D. affinis in several Floras ( Laundon 1959, 1970, 1978). After morphological analysis this work follows the Flora of Tropical Africa ( Oliver 1871) and treats D. flexicaulis as a separate species. Both species share the same habitat and have overlapping distributions.Additionally, hybrids of D. flexicaulis and D. affinis occur, which show characters of both parent species ( Robinson et al. 2017).

Figures

Fig. 7 Drosera flexicaulis Welw. ex Oliv. a. Leaf shape showing the slender petiole and the narrowly spathulate lamina; b. general morphology: long, slender stems with leaves held erect and laterally arising inflorescences; c. distribution according to the literature; d. province map of Angola and DRC with localities of examined herbarium specimens; e. pollen in tetrads with echinate, conical sculpture elements in low density. — Scale bars: a = 1 cm; b = 2 cm; e = 10 µm.